WO2003082503A2 - Method and device for machining a workpiece - Google Patents

Method and device for machining a workpiece

Info

Publication number
WO2003082503A2
WO2003082503A2 PCT/DE2003/000978 DE0300978W WO03082503A2 WO 2003082503 A2 WO2003082503 A2 WO 2003082503A2 DE 0300978 W DE0300978 W DE 0300978W WO 03082503 A2 WO03082503 A2 WO 03082503A2
Authority
WO
Grant status
Application
Patent type
Prior art keywords
flow
channel
mass
workpiece
machining
Prior art date
Application number
PCT/DE2003/000978
Other languages
German (de)
French (fr)
Other versions
WO2003082503A3 (en )
Inventor
Gerhard Moeckl
Martin Etzel
Original Assignee
Robert Bosch Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23HWORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
    • B23H9/00Machining specially adapted for treating particular metal objects or for obtaining special effects or results on metal objects
    • B23H9/14Making holes
    • B23H9/16Making holes using an electrolytic jet
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23HWORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
    • B23H9/00Machining specially adapted for treating particular metal objects or for obtaining special effects or results on metal objects

Abstract

The invention relates to a method for machining a workpiece (12) comprising a first flow channel (14) and a second flow channel (16). The second flow channel (16) opens into the first flow channel (14). A depression (46) is configured around the opening of the second flow channel (16) into the first flow channel (14). Said depression (46) is configured using an electrochemical material machining process. Material is simultaneously removed from the edge formed by the depression (46) and the second flow channel (16) until a predetermined mass flux of the electrolyte solution used for the electrochemical material machining process has been achieved through the second flow channel (16).

Description

Method and apparatus for machining a workpiece

State of the art

The invention relates to a method and an apparatus for producing a workpiece according to the preamble of the independent claims.

There is known a method for machining a workpiece, wherein the workpiece comprises a first flow channel and a second flow channel, said second flow channel opens into the first flow channel. Around the mouth of the second flow channel into the first flow channel, a reduction by means of electrical discharge machining is incorporated. This reduction may be necessary so that the turns of a first flow channel arranged in the spring does not block the second flow channel.

By electrical discharge machining the surface of the cut is very rough. The edge which is formed by the reduction and the second flow channel, is very different from workpiece to workpiece. This makes it possible to vary considerably between the amount of a flowing medium in later use at a given pressure from workpiece to workpiece. To achieve that, for example, via the flow channels of injection nozzles for internal combustion engines at a certain pressure, a precise amount of fuel is injected into the combustion chamber, several processes and devices are known.

For example, known from DE 689 16 552 T2, to pump between an electrode and the workpiece and through the at least one flow channel, an electrolyte, to modify the flow channel electrochemically and to achieve a certain so-called flow resistance through the flow channel during machining.

This so-called flow resistance is measured dynamically. Dynamically measuring means that the flow resistance is measured during machining, is removed in, for example, material from the wall or the edge of the flow channel. The measurement of the flow resistance for example, via the

Measuring the path of displacement of a piston whose surface is known. This increases the volume can be determined that flows through the flow channel. in other words, the flow rate is measured. Further, the determination of the flow resistance can also be effected in that the speed of the electrolytic solution is measured in the flow channel. As soon as a predetermined value of the volume flow or the velocity of the electrolytic solution is reached, the processing is ended.

In the Where 96/12586 has been recognized that arise in a dynamic measurement during electrochemical processing gas bubbles that have an influence on the measurement result. A static measurement is more accurate other hand, as a measurement of the volume flow takes place during the pauses so that the result is not affected by gas bubbles.

However, according to this document, the volumetric flow is measured. In the measurement of the volume flow has the

Temperature a strong Ξinfluss on the result. Ie, at high temperatures, a larger volume flow is measured as at lower temperatures.

Advantages of the Invention

In contrast, the inventive method and the inventive apparatus for processing a workpiece with the characterizing features of the independent claims have the advantage that a more economical and at the same time accurate manufacturing are possible.

For this, the current flowing through the at least one flow channel mass flow of the electrolyte solution is measured as well as simultaneously incorporated lowering and as long as the processing carried out until a predetermined mass flow is achieved.

The measurement of the mass flow is more accurate if it occurs during the pauses, wherein the measurement in the respective processing interval begins only after a settling time of the mass flow.

In the apparatus means for measuring the mass flow of the working fluid through the at least one flow channel is present. The device is a mass flow meter which operates according to the Coriolis principle.

The apparatus has a simple construction, when a piston diaphragm pump pumps the working fluid flow channel through the at least. Characterized pressure fluctuations are reduced during measurement.

In order to reduce pressure peaks even further pulsation damper to smooth pressure fluctuations can be arranged.

Further advantages and advantageous developments of the method and apparatus of the invention for machining a workpiece will be apparent from the dependent claims and the description.

drawing

An embodiment of the invention is illustrated in the drawing and explained in more detail in the following description. Show it:

1 shows a device for electrochemically machining, Figure 2 shows a pen in the section before the electrochemical

Processing and 3, a spring holder in section according to the electrochemical machining.

Description of the embodiment

1 shows an apparatus 10 for electrochemically machining a workpiece 12 is shown schematically. The principle of the electrochemical process due to the fact that two electrodes as in a

are working liquid aqueous electrolyte solution used, a DC voltage is applied. For this purpose the workpiece to be treated 12 with the aid of a transmission element to the positive pole (anode) is connected to the power source, while serving as a tool electrode is connected to the power source because of their electrically conductive properties to the negative pole (cathode).

The composition of the electrolyte solution depends on the material of the component to be machined. For metals such. Is selected as a saline solution or a solution of sodium nitrate. The electrochemical process itself is known from physics and therefore not explained in detail here. The operation is dependent not only on the composition of the electrolyte solution also on the used current, which in turn is matched to the material of the workpiece to be machined 12th

The workpiece 12 is formed in the present embodiment as a spring holder of an injection nozzle. This is a cylindrical member having a central blind bore 14 and an outlet hole 16 for branching off the excess, not injected into the combustion chamber of the engine during the combustion process fuel. Instead of a more outlet holes may be present.

At the bottom of the blind bore 14 a spring, not shown, is supported. Instead of being designed as a spring holder blank 12 may also be at other than the reaching into the combustion chamber front part of an injection nozzle. In such a part, it is also one of the blind hole 14 similar bore 16 branch off similar injection bores of the usually more of the discharge bore. It concerns with the discharge bore 16 or the injection holes to flow channels which are to be machined electrochemically with the device 10 degrees.

The apparatus 10 comprises a tank 18, a pump 20, pulsation dampener 22, a pressure gauge 24, a safety valve 26, a mass flow meter 28, an electrode 30 and a generator 32 for the voltage and current supply. The components mentioned are connected to a not shown, and known per se PLC (programmable logic controller; in English Programmable Logic Controller, abbreviated to PLC) connected, with which the device can operate 10th Alternatively, the use of another for this purpose suitable computer, such as an industrial PC, would be conceivable.

The pump 20 pumps the required electrochemical machining electrolytic solution from the tank 18 via a line 34 into a conduit 36. The conduit 36 ​​leads to the workpiece 12. The electrolyte solution is prepared by the

Blind hole 14 and the drain bore 16 pumped. From there, the electrolyte solution flows back into the tank 18. The pump 20 is a single-stage or multi-stage piston diaphragm pump. Piston diaphragm pumps are characterized by particularly low pressure fluctuations.

In addition, 36 pulsation dampener 22 to smooth out fluctuations in pressure are provided on the line. Run the pressure fluctuations generated by the pump 20 but within acceptable limits, the pulsation damper 22 can also be omitted.

By means of the arranged after the pulsation dampers 22 on the line 36 pressure gauge 24, the pressure of the electrolyte solution is detected and passed for evaluation to an unillustrated controller. but the pressure can also be processed in a control which regulates the pressure in the system based on process requirements. The connected also to the line 36 a safety valve 26 is needed for the case that the pressure control fails and an overpressure arises in the system. In this case, the safety valve 26 opens automatically and can flow out which is under excessive pressure electrolyte solution.

The mass flow meter 28 due to the action of the physical magnitude of the Coriolis force. The Coriolis force is a Scheinkraft which engages masses moved in a rotating reference system. Therefore, in the measurement technique, the medium to be detected is conducted in a vibrated pipe. Depending on the mass flow flowing through the Coriolis force affects the resulting deflection of the tube. This deflection is detected by sensors. Phase shifts of the sensor signals provide a voltage proportional to the actual mass flow is size. An designs, there is one and two pipe systems as well as different geometric shapes of the pipe such as a straight tube, a tube in zigzag form, in loops, etc.

The great advantage of this measuring principle compared to the measurement of flow rates, or pressure drops that it and independent of density, temperature, viscosity, pressure

is conductivity. It is possible to determine the density and temperature of a mass even slightly. Furthermore, especially in the field of fuel injection is not the volume but the injected mass critical to the chemical reactions in a combustion process. If you have information on the mass flow, the chemical reactions during the combustion process can be better accounted for, thus optimizing. For voltage and power supply of the generator 32 is used, which can be freely programmed via the unillustrated PLC. the electrode 30 and the workpiece 12 are connected to the generator 32nd Through the electrode 30, the electrolyte solution and the workpiece 12, the material removal necessary for current to flow.

In the sectional view of Figure 2, the structure of the electrode 30 is more apparent. The electrode 30 comprises a copper tube 38 which is surrounded by an insulation 40th At the point at which the machining operation is to take place, the copper tube 38 is exposed and has a Durchläse 42 in the form of a bore. Thus, the electrolyte solution through the copper pipe 38, the Durchläse 42 and flow through the outlet bore sixteenth The location on the electrode to which the copper tube 38 is exposed, the effective electrode surface 44. The effective electrode area 44 is significantly involved in the size of the machining surface of the workpiece 12th

In the processing, as will be seen from Figure 3, the area of ​​the blind bore 14, which is located around the outlet hole 16, removed. This gives rise to a reduction or a pocket 46. The pocket 46 is necessary so that the above-mentioned, unillustrated spring, which is supported on the base of the blind bore 14, the outlet hole 16 may not block.

When machining of the workpiece 12 will now be moved so that the mass flow of electrolyte solution through the

The outlet hole 16 is measured and the electrochemical machining is performed until a predetermined mass flow is achieved. The mass flow of the electrolyte solution uence only on the density ratios with the required mass flow of fuel to be converted. This ensures that the desired mass flow is achieved through the outlet bore 16 at the end by the processing at a predetermined pressure always is obtained. is important for the change of the mass flow, the variation of the edge formed by the reduction or the pocket 46 and the outlet bore sixteenth takes the longer the processing, the larger the radius, and the more large, the mass flow. The change of the mass flow over time was a total asymptotically extending and approach a substantially by the narrowest point of the outlet hole 16 certain value. This value was substantially remain constant until the electrochemical machining has progressed so far that the diameter of the outlet 16 increases again.

In detail the procedure is such that the first pump is switched on 20th The electrolyte solution is pumped through lines 34, 36 to the workpiece 12 and through the bores 14, 16th The electrode 30 and the workpiece 12 form a working gap through which the electrolyte solution is pumped. Once the electrolytic solution has reached a predetermined temperature, the generator 32 is turned on. By the current flow material is removed at the edge of the outlet hole 16 and washed away by the electrolyte solution.

Simultaneously with the rounding of the edge of the outlet hole 16, which - as already mentioned - opens into the blind bore 14, the pocket is incorporated around the edge of the outlet 16 around the 46th The bag 46 is usually incorporated in the electric discharge machining process whereby a mass flow calibration is not possible. The processing by means of electro-erosion is relatively inaccurate. By the electrochemical material processing, the accuracy of machining is now increased and there are two operations combined into a single operation. It is 16 bore and the reduction or pocket 46 at the same time removed from the edge of the outlet as long material to the predetermined mass flow of the electrolyte solution used for the electrochemical material processing through the outlet bore 16 bore is reached. that the voltage of the generator 32 is set so is important that, for achieving the desired mass flow, the pocket 46 is too shallow or too deep.

In the processing of the generator 32 is switched off after a first predetermined time. That is, in order to obtain accurate results is not a dynamic measurement, which may be distorted by gas bubbling is carried out, but a static measurement. So to achieve this,

Measuring the mass flow during the pauses, wherein the measurement in the respective processing interval begins only after a settling time of the mass flow. This settling time is in the range of a few tenths of a second to several seconds. When the mass flow is reached at a predetermined pressure, the processing is terminated. If the desired mass flow not reached, followed by a further processing phase, after also carried out a processing break with a settling phase and a measurement phase. The operations are repeated until the desired mass flow is achieved.

For a more economical production, the electrolytic solution may be pumped at a lower pressure during the machining phases than during the

The pauses. In the processing phase, the pressure can for example be at Lobar and in the machining intervals or measurement phases at 80bar. The parts made by this method can recognize it is easy to see that the bag 46 and the edge of the reduction 46 and the second flow channel 16 formed have a very smooth surface. This surface is considerably smoother than a bag produced by means of electroerosion 46. Also, the surface of the bag is generally smoother than that produced by rotating surface of the blind bore fourteenth

Important in the apparatus 10 for processing at least a flow channel (discharge hole 16) of the workpiece 12 with a working fluid is that a device for measuring the mass flow (mass flow meter 28) of the working liquid (electrolyte solution) through the at least one flow channel (discharge hole 16) is present. This very precise work results can be achieved.

reference numeral

10 device 30 electrode

12 workpiece 32 Generator

14 blind hole 34 line

16 outlet hole 36 line

18 tank 38 copper tube

20 pump 40 insulation

Pulsation damper 22 42 passage

24 pressure gauge 44 effective electrode surface

26 Safety valve 46 bag

28 mass flow meter

Claims

claims
1. A method for machining a workpiece (12) having a first flow channel (14) and a second flow channel (16), wherein the second flow channel (16) opens into the first flow channel (14) and (around the mouth of the second flow channel 16) is incorporated a reduction (46) in the first flow channel (14), characterized in that the depression (46) is worked by means of the electrochemical material machining process and at the same time (from the (from the reduction 46) and the second flow channel 16) formed border as long as material is removed, until it reaches a predetermined mass flow of the electrolyte solution used for the electrochemical material processing through the second flow channel (16).
2. The method according to claim 1, characterized in that the measurement of the mass flow takes place during the pauses, wherein the measurement in the respective processing interval begins only after a settling time of the mass flow.
3. The method of claim 1 or 2, characterized in that the working liquid is pumped during the machining phase at a lower pressure than during processing pauses.
4. The device (10) for processing at least a flow channel (16) of a workpiece (12) at least with a working fluid, characterized in that a device (28) for measuring the mass flow of the working fluid through the at least one flow channel
(16) is present.
5. The apparatus (10) according to claim 4, characterized in that a piston membrane pump (20) pumps the working fluid through the at least one flow channel (16).
6. The apparatus (10) according to claim 5 or 6, characterized in that the pulsation damper (22) are provided for smoothing of pressure fluctuations.
7. Device (10) according to any one of claims 4 to 6, characterized in that the working liquid is an electrolyte solution.
PCT/DE2003/000978 2002-04-03 2003-03-25 Method and device for machining a workpiece WO2003082503A3 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE10214617.9 2002-04-03
DE2002114617 DE10214617A1 (en) 2002-04-03 2002-04-03 Method and apparatus for machining a workpiece

Publications (2)

Publication Number Publication Date
WO2003082503A2 true true WO2003082503A2 (en) 2003-10-09
WO2003082503A3 true WO2003082503A3 (en) 2003-12-04

Family

ID=28051052

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE2003/000978 WO2003082503A3 (en) 2002-04-03 2003-03-25 Method and device for machining a workpiece

Country Status (2)

Country Link
DE (1) DE10214617A1 (en)
WO (1) WO2003082503A3 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5865977A (en) * 1994-10-21 1999-02-02 Frembgen; Fritz-Herbert Process for the electrochemical treatment of flow channels in metal workpieces
EP1179379A1 (en) * 2000-08-09 2002-02-13 Delphi Technologies, Inc. Electrochemical machining of orificies

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5865977A (en) * 1994-10-21 1999-02-02 Frembgen; Fritz-Herbert Process for the electrochemical treatment of flow channels in metal workpieces
EP1179379A1 (en) * 2000-08-09 2002-02-13 Delphi Technologies, Inc. Electrochemical machining of orificies

Also Published As

Publication number Publication date Type
WO2003082503A3 (en) 2003-12-04 application
DE10214617A1 (en) 2003-10-16 application

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